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Merge remote-tracking branches 'asoc/topic/cs4265', 'asoc/topic/cs42l56', 'asoc/topic...
[deliverable/linux.git] / drivers / net / xen-netback / netback.c
1 /*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35 #include "common.h"
36
37 #include <linux/kthread.h>
38 #include <linux/if_vlan.h>
39 #include <linux/udp.h>
40 #include <linux/highmem.h>
41
42 #include <net/tcp.h>
43
44 #include <xen/xen.h>
45 #include <xen/events.h>
46 #include <xen/interface/memory.h>
47
48 #include <asm/xen/hypercall.h>
49 #include <asm/xen/page.h>
50
51 /* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
53 * enabled by default.
54 */
55 bool separate_tx_rx_irq = 1;
56 module_param(separate_tx_rx_irq, bool, 0644);
57
58 /* When guest ring is filled up, qdisc queues the packets for us, but we have
59 * to timeout them, otherwise other guests' packets can get stuck there
60 */
61 unsigned int rx_drain_timeout_msecs = 10000;
62 module_param(rx_drain_timeout_msecs, uint, 0444);
63 unsigned int rx_drain_timeout_jiffies;
64
65 unsigned int xenvif_max_queues;
66 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
67 MODULE_PARM_DESC(max_queues,
68 "Maximum number of queues per virtual interface");
69
70 /*
71 * This is the maximum slots a skb can have. If a guest sends a skb
72 * which exceeds this limit it is considered malicious.
73 */
74 #define FATAL_SKB_SLOTS_DEFAULT 20
75 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
76 module_param(fatal_skb_slots, uint, 0444);
77
78 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
79 u8 status);
80
81 static void make_tx_response(struct xenvif_queue *queue,
82 struct xen_netif_tx_request *txp,
83 s8 st);
84
85 static inline int tx_work_todo(struct xenvif_queue *queue);
86 static inline int rx_work_todo(struct xenvif_queue *queue);
87
88 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
89 u16 id,
90 s8 st,
91 u16 offset,
92 u16 size,
93 u16 flags);
94
95 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
96 u16 idx)
97 {
98 return page_to_pfn(queue->mmap_pages[idx]);
99 }
100
101 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
102 u16 idx)
103 {
104 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
105 }
106
107 #define callback_param(vif, pending_idx) \
108 (vif->pending_tx_info[pending_idx].callback_struct)
109
110 /* Find the containing VIF's structure from a pointer in pending_tx_info array
111 */
112 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
113 {
114 u16 pending_idx = ubuf->desc;
115 struct pending_tx_info *temp =
116 container_of(ubuf, struct pending_tx_info, callback_struct);
117 return container_of(temp - pending_idx,
118 struct xenvif_queue,
119 pending_tx_info[0]);
120 }
121
122 /* This is a miniumum size for the linear area to avoid lots of
123 * calls to __pskb_pull_tail() as we set up checksum offsets. The
124 * value 128 was chosen as it covers all IPv4 and most likely
125 * IPv6 headers.
126 */
127 #define PKT_PROT_LEN 128
128
129 static u16 frag_get_pending_idx(skb_frag_t *frag)
130 {
131 return (u16)frag->page_offset;
132 }
133
134 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
135 {
136 frag->page_offset = pending_idx;
137 }
138
139 static inline pending_ring_idx_t pending_index(unsigned i)
140 {
141 return i & (MAX_PENDING_REQS-1);
142 }
143
144 bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
145 {
146 RING_IDX prod, cons;
147
148 do {
149 prod = queue->rx.sring->req_prod;
150 cons = queue->rx.req_cons;
151
152 if (prod - cons >= needed)
153 return true;
154
155 queue->rx.sring->req_event = prod + 1;
156
157 /* Make sure event is visible before we check prod
158 * again.
159 */
160 mb();
161 } while (queue->rx.sring->req_prod != prod);
162
163 return false;
164 }
165
166 /*
167 * Returns true if we should start a new receive buffer instead of
168 * adding 'size' bytes to a buffer which currently contains 'offset'
169 * bytes.
170 */
171 static bool start_new_rx_buffer(int offset, unsigned long size, int head,
172 bool full_coalesce)
173 {
174 /* simple case: we have completely filled the current buffer. */
175 if (offset == MAX_BUFFER_OFFSET)
176 return true;
177
178 /*
179 * complex case: start a fresh buffer if the current frag
180 * would overflow the current buffer but only if:
181 * (i) this frag would fit completely in the next buffer
182 * and (ii) there is already some data in the current buffer
183 * and (iii) this is not the head buffer.
184 * and (iv) there is no need to fully utilize the buffers
185 *
186 * Where:
187 * - (i) stops us splitting a frag into two copies
188 * unless the frag is too large for a single buffer.
189 * - (ii) stops us from leaving a buffer pointlessly empty.
190 * - (iii) stops us leaving the first buffer
191 * empty. Strictly speaking this is already covered
192 * by (ii) but is explicitly checked because
193 * netfront relies on the first buffer being
194 * non-empty and can crash otherwise.
195 * - (iv) is needed for skbs which can use up more than MAX_SKB_FRAGS
196 * slot
197 *
198 * This means we will effectively linearise small
199 * frags but do not needlessly split large buffers
200 * into multiple copies tend to give large frags their
201 * own buffers as before.
202 */
203 BUG_ON(size > MAX_BUFFER_OFFSET);
204 if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head &&
205 !full_coalesce)
206 return true;
207
208 return false;
209 }
210
211 struct netrx_pending_operations {
212 unsigned copy_prod, copy_cons;
213 unsigned meta_prod, meta_cons;
214 struct gnttab_copy *copy;
215 struct xenvif_rx_meta *meta;
216 int copy_off;
217 grant_ref_t copy_gref;
218 };
219
220 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
221 struct netrx_pending_operations *npo)
222 {
223 struct xenvif_rx_meta *meta;
224 struct xen_netif_rx_request *req;
225
226 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
227
228 meta = npo->meta + npo->meta_prod++;
229 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
230 meta->gso_size = 0;
231 meta->size = 0;
232 meta->id = req->id;
233
234 npo->copy_off = 0;
235 npo->copy_gref = req->gref;
236
237 return meta;
238 }
239
240 struct xenvif_rx_cb {
241 int meta_slots_used;
242 bool full_coalesce;
243 };
244
245 #define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
246
247 /*
248 * Set up the grant operations for this fragment. If it's a flipping
249 * interface, we also set up the unmap request from here.
250 */
251 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
252 struct netrx_pending_operations *npo,
253 struct page *page, unsigned long size,
254 unsigned long offset, int *head,
255 struct xenvif_queue *foreign_queue,
256 grant_ref_t foreign_gref)
257 {
258 struct gnttab_copy *copy_gop;
259 struct xenvif_rx_meta *meta;
260 unsigned long bytes;
261 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
262
263 /* Data must not cross a page boundary. */
264 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
265
266 meta = npo->meta + npo->meta_prod - 1;
267
268 /* Skip unused frames from start of page */
269 page += offset >> PAGE_SHIFT;
270 offset &= ~PAGE_MASK;
271
272 while (size > 0) {
273 BUG_ON(offset >= PAGE_SIZE);
274 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
275
276 bytes = PAGE_SIZE - offset;
277
278 if (bytes > size)
279 bytes = size;
280
281 if (start_new_rx_buffer(npo->copy_off,
282 bytes,
283 *head,
284 XENVIF_RX_CB(skb)->full_coalesce)) {
285 /*
286 * Netfront requires there to be some data in the head
287 * buffer.
288 */
289 BUG_ON(*head);
290
291 meta = get_next_rx_buffer(queue, npo);
292 }
293
294 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
295 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
296
297 copy_gop = npo->copy + npo->copy_prod++;
298 copy_gop->flags = GNTCOPY_dest_gref;
299 copy_gop->len = bytes;
300
301 if (foreign_queue) {
302 copy_gop->source.domid = foreign_queue->vif->domid;
303 copy_gop->source.u.ref = foreign_gref;
304 copy_gop->flags |= GNTCOPY_source_gref;
305 } else {
306 copy_gop->source.domid = DOMID_SELF;
307 copy_gop->source.u.gmfn =
308 virt_to_mfn(page_address(page));
309 }
310 copy_gop->source.offset = offset;
311
312 copy_gop->dest.domid = queue->vif->domid;
313 copy_gop->dest.offset = npo->copy_off;
314 copy_gop->dest.u.ref = npo->copy_gref;
315
316 npo->copy_off += bytes;
317 meta->size += bytes;
318
319 offset += bytes;
320 size -= bytes;
321
322 /* Next frame */
323 if (offset == PAGE_SIZE && size) {
324 BUG_ON(!PageCompound(page));
325 page++;
326 offset = 0;
327 }
328
329 /* Leave a gap for the GSO descriptor. */
330 if (skb_is_gso(skb)) {
331 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
332 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
333 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
334 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
335 }
336
337 if (*head && ((1 << gso_type) & queue->vif->gso_mask))
338 queue->rx.req_cons++;
339
340 *head = 0; /* There must be something in this buffer now. */
341
342 }
343 }
344
345 /*
346 * Find the grant ref for a given frag in a chain of struct ubuf_info's
347 * skb: the skb itself
348 * i: the frag's number
349 * ubuf: a pointer to an element in the chain. It should not be NULL
350 *
351 * Returns a pointer to the element in the chain where the page were found. If
352 * not found, returns NULL.
353 * See the definition of callback_struct in common.h for more details about
354 * the chain.
355 */
356 static const struct ubuf_info *xenvif_find_gref(const struct sk_buff *const skb,
357 const int i,
358 const struct ubuf_info *ubuf)
359 {
360 struct xenvif_queue *foreign_queue = ubuf_to_queue(ubuf);
361
362 do {
363 u16 pending_idx = ubuf->desc;
364
365 if (skb_shinfo(skb)->frags[i].page.p ==
366 foreign_queue->mmap_pages[pending_idx])
367 break;
368 ubuf = (struct ubuf_info *) ubuf->ctx;
369 } while (ubuf);
370
371 return ubuf;
372 }
373
374 /*
375 * Prepare an SKB to be transmitted to the frontend.
376 *
377 * This function is responsible for allocating grant operations, meta
378 * structures, etc.
379 *
380 * It returns the number of meta structures consumed. The number of
381 * ring slots used is always equal to the number of meta slots used
382 * plus the number of GSO descriptors used. Currently, we use either
383 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
384 * frontend-side LRO).
385 */
386 static int xenvif_gop_skb(struct sk_buff *skb,
387 struct netrx_pending_operations *npo,
388 struct xenvif_queue *queue)
389 {
390 struct xenvif *vif = netdev_priv(skb->dev);
391 int nr_frags = skb_shinfo(skb)->nr_frags;
392 int i;
393 struct xen_netif_rx_request *req;
394 struct xenvif_rx_meta *meta;
395 unsigned char *data;
396 int head = 1;
397 int old_meta_prod;
398 int gso_type;
399 const struct ubuf_info *ubuf = skb_shinfo(skb)->destructor_arg;
400 const struct ubuf_info *const head_ubuf = ubuf;
401
402 old_meta_prod = npo->meta_prod;
403
404 gso_type = XEN_NETIF_GSO_TYPE_NONE;
405 if (skb_is_gso(skb)) {
406 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
407 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
408 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
409 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
410 }
411
412 /* Set up a GSO prefix descriptor, if necessary */
413 if ((1 << gso_type) & vif->gso_prefix_mask) {
414 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
415 meta = npo->meta + npo->meta_prod++;
416 meta->gso_type = gso_type;
417 meta->gso_size = skb_shinfo(skb)->gso_size;
418 meta->size = 0;
419 meta->id = req->id;
420 }
421
422 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
423 meta = npo->meta + npo->meta_prod++;
424
425 if ((1 << gso_type) & vif->gso_mask) {
426 meta->gso_type = gso_type;
427 meta->gso_size = skb_shinfo(skb)->gso_size;
428 } else {
429 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
430 meta->gso_size = 0;
431 }
432
433 meta->size = 0;
434 meta->id = req->id;
435 npo->copy_off = 0;
436 npo->copy_gref = req->gref;
437
438 data = skb->data;
439 while (data < skb_tail_pointer(skb)) {
440 unsigned int offset = offset_in_page(data);
441 unsigned int len = PAGE_SIZE - offset;
442
443 if (data + len > skb_tail_pointer(skb))
444 len = skb_tail_pointer(skb) - data;
445
446 xenvif_gop_frag_copy(queue, skb, npo,
447 virt_to_page(data), len, offset, &head,
448 NULL,
449 0);
450 data += len;
451 }
452
453 for (i = 0; i < nr_frags; i++) {
454 /* This variable also signals whether foreign_gref has a real
455 * value or not.
456 */
457 struct xenvif_queue *foreign_queue = NULL;
458 grant_ref_t foreign_gref;
459
460 if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) &&
461 (ubuf->callback == &xenvif_zerocopy_callback)) {
462 const struct ubuf_info *const startpoint = ubuf;
463
464 /* Ideally ubuf points to the chain element which
465 * belongs to this frag. Or if frags were removed from
466 * the beginning, then shortly before it.
467 */
468 ubuf = xenvif_find_gref(skb, i, ubuf);
469
470 /* Try again from the beginning of the list, if we
471 * haven't tried from there. This only makes sense in
472 * the unlikely event of reordering the original frags.
473 * For injected local pages it's an unnecessary second
474 * run.
475 */
476 if (unlikely(!ubuf) && startpoint != head_ubuf)
477 ubuf = xenvif_find_gref(skb, i, head_ubuf);
478
479 if (likely(ubuf)) {
480 u16 pending_idx = ubuf->desc;
481
482 foreign_queue = ubuf_to_queue(ubuf);
483 foreign_gref =
484 foreign_queue->pending_tx_info[pending_idx].req.gref;
485 /* Just a safety measure. If this was the last
486 * element on the list, the for loop will
487 * iterate again if a local page were added to
488 * the end. Using head_ubuf here prevents the
489 * second search on the chain. Or the original
490 * frags changed order, but that's less likely.
491 * In any way, ubuf shouldn't be NULL.
492 */
493 ubuf = ubuf->ctx ?
494 (struct ubuf_info *) ubuf->ctx :
495 head_ubuf;
496 } else
497 /* This frag was a local page, added to the
498 * array after the skb left netback.
499 */
500 ubuf = head_ubuf;
501 }
502 xenvif_gop_frag_copy(queue, skb, npo,
503 skb_frag_page(&skb_shinfo(skb)->frags[i]),
504 skb_frag_size(&skb_shinfo(skb)->frags[i]),
505 skb_shinfo(skb)->frags[i].page_offset,
506 &head,
507 foreign_queue,
508 foreign_queue ? foreign_gref : UINT_MAX);
509 }
510
511 return npo->meta_prod - old_meta_prod;
512 }
513
514 /*
515 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
516 * used to set up the operations on the top of
517 * netrx_pending_operations, which have since been done. Check that
518 * they didn't give any errors and advance over them.
519 */
520 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
521 struct netrx_pending_operations *npo)
522 {
523 struct gnttab_copy *copy_op;
524 int status = XEN_NETIF_RSP_OKAY;
525 int i;
526
527 for (i = 0; i < nr_meta_slots; i++) {
528 copy_op = npo->copy + npo->copy_cons++;
529 if (copy_op->status != GNTST_okay) {
530 netdev_dbg(vif->dev,
531 "Bad status %d from copy to DOM%d.\n",
532 copy_op->status, vif->domid);
533 status = XEN_NETIF_RSP_ERROR;
534 }
535 }
536
537 return status;
538 }
539
540 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
541 struct xenvif_rx_meta *meta,
542 int nr_meta_slots)
543 {
544 int i;
545 unsigned long offset;
546
547 /* No fragments used */
548 if (nr_meta_slots <= 1)
549 return;
550
551 nr_meta_slots--;
552
553 for (i = 0; i < nr_meta_slots; i++) {
554 int flags;
555 if (i == nr_meta_slots - 1)
556 flags = 0;
557 else
558 flags = XEN_NETRXF_more_data;
559
560 offset = 0;
561 make_rx_response(queue, meta[i].id, status, offset,
562 meta[i].size, flags);
563 }
564 }
565
566 void xenvif_kick_thread(struct xenvif_queue *queue)
567 {
568 wake_up(&queue->wq);
569 }
570
571 static void xenvif_rx_action(struct xenvif_queue *queue)
572 {
573 s8 status;
574 u16 flags;
575 struct xen_netif_rx_response *resp;
576 struct sk_buff_head rxq;
577 struct sk_buff *skb;
578 LIST_HEAD(notify);
579 int ret;
580 unsigned long offset;
581 bool need_to_notify = false;
582
583 struct netrx_pending_operations npo = {
584 .copy = queue->grant_copy_op,
585 .meta = queue->meta,
586 };
587
588 skb_queue_head_init(&rxq);
589
590 while ((skb = skb_dequeue(&queue->rx_queue)) != NULL) {
591 RING_IDX max_slots_needed;
592 RING_IDX old_req_cons;
593 RING_IDX ring_slots_used;
594 int i;
595
596 /* We need a cheap worse case estimate for the number of
597 * slots we'll use.
598 */
599
600 max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) +
601 skb_headlen(skb),
602 PAGE_SIZE);
603 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
604 unsigned int size;
605 unsigned int offset;
606
607 size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
608 offset = skb_shinfo(skb)->frags[i].page_offset;
609
610 /* For a worse-case estimate we need to factor in
611 * the fragment page offset as this will affect the
612 * number of times xenvif_gop_frag_copy() will
613 * call start_new_rx_buffer().
614 */
615 max_slots_needed += DIV_ROUND_UP(offset + size,
616 PAGE_SIZE);
617 }
618
619 /* To avoid the estimate becoming too pessimal for some
620 * frontends that limit posted rx requests, cap the estimate
621 * at MAX_SKB_FRAGS. In this case netback will fully coalesce
622 * the skb into the provided slots.
623 */
624 if (max_slots_needed > MAX_SKB_FRAGS) {
625 max_slots_needed = MAX_SKB_FRAGS;
626 XENVIF_RX_CB(skb)->full_coalesce = true;
627 } else {
628 XENVIF_RX_CB(skb)->full_coalesce = false;
629 }
630
631 /* We may need one more slot for GSO metadata */
632 if (skb_is_gso(skb) &&
633 (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
634 skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
635 max_slots_needed++;
636
637 /* If the skb may not fit then bail out now */
638 if (!xenvif_rx_ring_slots_available(queue, max_slots_needed)) {
639 skb_queue_head(&queue->rx_queue, skb);
640 need_to_notify = true;
641 queue->rx_last_skb_slots = max_slots_needed;
642 break;
643 } else
644 queue->rx_last_skb_slots = 0;
645
646 old_req_cons = queue->rx.req_cons;
647 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
648 ring_slots_used = queue->rx.req_cons - old_req_cons;
649
650 BUG_ON(ring_slots_used > max_slots_needed);
651
652 __skb_queue_tail(&rxq, skb);
653 }
654
655 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
656
657 if (!npo.copy_prod)
658 goto done;
659
660 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
661 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
662
663 while ((skb = __skb_dequeue(&rxq)) != NULL) {
664
665 if ((1 << queue->meta[npo.meta_cons].gso_type) &
666 queue->vif->gso_prefix_mask) {
667 resp = RING_GET_RESPONSE(&queue->rx,
668 queue->rx.rsp_prod_pvt++);
669
670 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
671
672 resp->offset = queue->meta[npo.meta_cons].gso_size;
673 resp->id = queue->meta[npo.meta_cons].id;
674 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
675
676 npo.meta_cons++;
677 XENVIF_RX_CB(skb)->meta_slots_used--;
678 }
679
680
681 queue->stats.tx_bytes += skb->len;
682 queue->stats.tx_packets++;
683
684 status = xenvif_check_gop(queue->vif,
685 XENVIF_RX_CB(skb)->meta_slots_used,
686 &npo);
687
688 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
689 flags = 0;
690 else
691 flags = XEN_NETRXF_more_data;
692
693 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
694 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
695 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
696 /* remote but checksummed. */
697 flags |= XEN_NETRXF_data_validated;
698
699 offset = 0;
700 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
701 status, offset,
702 queue->meta[npo.meta_cons].size,
703 flags);
704
705 if ((1 << queue->meta[npo.meta_cons].gso_type) &
706 queue->vif->gso_mask) {
707 struct xen_netif_extra_info *gso =
708 (struct xen_netif_extra_info *)
709 RING_GET_RESPONSE(&queue->rx,
710 queue->rx.rsp_prod_pvt++);
711
712 resp->flags |= XEN_NETRXF_extra_info;
713
714 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
715 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
716 gso->u.gso.pad = 0;
717 gso->u.gso.features = 0;
718
719 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
720 gso->flags = 0;
721 }
722
723 xenvif_add_frag_responses(queue, status,
724 queue->meta + npo.meta_cons + 1,
725 XENVIF_RX_CB(skb)->meta_slots_used);
726
727 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
728
729 need_to_notify |= !!ret;
730
731 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
732 dev_kfree_skb(skb);
733 }
734
735 done:
736 if (need_to_notify)
737 notify_remote_via_irq(queue->rx_irq);
738 }
739
740 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
741 {
742 int more_to_do;
743
744 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
745
746 if (more_to_do)
747 napi_schedule(&queue->napi);
748 }
749
750 static void tx_add_credit(struct xenvif_queue *queue)
751 {
752 unsigned long max_burst, max_credit;
753
754 /*
755 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
756 * Otherwise the interface can seize up due to insufficient credit.
757 */
758 max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size;
759 max_burst = min(max_burst, 131072UL);
760 max_burst = max(max_burst, queue->credit_bytes);
761
762 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
763 max_credit = queue->remaining_credit + queue->credit_bytes;
764 if (max_credit < queue->remaining_credit)
765 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
766
767 queue->remaining_credit = min(max_credit, max_burst);
768 }
769
770 static void tx_credit_callback(unsigned long data)
771 {
772 struct xenvif_queue *queue = (struct xenvif_queue *)data;
773 tx_add_credit(queue);
774 xenvif_napi_schedule_or_enable_events(queue);
775 }
776
777 static void xenvif_tx_err(struct xenvif_queue *queue,
778 struct xen_netif_tx_request *txp, RING_IDX end)
779 {
780 RING_IDX cons = queue->tx.req_cons;
781 unsigned long flags;
782
783 do {
784 spin_lock_irqsave(&queue->response_lock, flags);
785 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
786 spin_unlock_irqrestore(&queue->response_lock, flags);
787 if (cons == end)
788 break;
789 txp = RING_GET_REQUEST(&queue->tx, cons++);
790 } while (1);
791 queue->tx.req_cons = cons;
792 }
793
794 static void xenvif_fatal_tx_err(struct xenvif *vif)
795 {
796 netdev_err(vif->dev, "fatal error; disabling device\n");
797 vif->disabled = true;
798 /* Disable the vif from queue 0's kthread */
799 if (vif->queues)
800 xenvif_kick_thread(&vif->queues[0]);
801 }
802
803 static int xenvif_count_requests(struct xenvif_queue *queue,
804 struct xen_netif_tx_request *first,
805 struct xen_netif_tx_request *txp,
806 int work_to_do)
807 {
808 RING_IDX cons = queue->tx.req_cons;
809 int slots = 0;
810 int drop_err = 0;
811 int more_data;
812
813 if (!(first->flags & XEN_NETTXF_more_data))
814 return 0;
815
816 do {
817 struct xen_netif_tx_request dropped_tx = { 0 };
818
819 if (slots >= work_to_do) {
820 netdev_err(queue->vif->dev,
821 "Asked for %d slots but exceeds this limit\n",
822 work_to_do);
823 xenvif_fatal_tx_err(queue->vif);
824 return -ENODATA;
825 }
826
827 /* This guest is really using too many slots and
828 * considered malicious.
829 */
830 if (unlikely(slots >= fatal_skb_slots)) {
831 netdev_err(queue->vif->dev,
832 "Malicious frontend using %d slots, threshold %u\n",
833 slots, fatal_skb_slots);
834 xenvif_fatal_tx_err(queue->vif);
835 return -E2BIG;
836 }
837
838 /* Xen network protocol had implicit dependency on
839 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
840 * the historical MAX_SKB_FRAGS value 18 to honor the
841 * same behavior as before. Any packet using more than
842 * 18 slots but less than fatal_skb_slots slots is
843 * dropped
844 */
845 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
846 if (net_ratelimit())
847 netdev_dbg(queue->vif->dev,
848 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
849 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
850 drop_err = -E2BIG;
851 }
852
853 if (drop_err)
854 txp = &dropped_tx;
855
856 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots),
857 sizeof(*txp));
858
859 /* If the guest submitted a frame >= 64 KiB then
860 * first->size overflowed and following slots will
861 * appear to be larger than the frame.
862 *
863 * This cannot be fatal error as there are buggy
864 * frontends that do this.
865 *
866 * Consume all slots and drop the packet.
867 */
868 if (!drop_err && txp->size > first->size) {
869 if (net_ratelimit())
870 netdev_dbg(queue->vif->dev,
871 "Invalid tx request, slot size %u > remaining size %u\n",
872 txp->size, first->size);
873 drop_err = -EIO;
874 }
875
876 first->size -= txp->size;
877 slots++;
878
879 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
880 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
881 txp->offset, txp->size);
882 xenvif_fatal_tx_err(queue->vif);
883 return -EINVAL;
884 }
885
886 more_data = txp->flags & XEN_NETTXF_more_data;
887
888 if (!drop_err)
889 txp++;
890
891 } while (more_data);
892
893 if (drop_err) {
894 xenvif_tx_err(queue, first, cons + slots);
895 return drop_err;
896 }
897
898 return slots;
899 }
900
901
902 struct xenvif_tx_cb {
903 u16 pending_idx;
904 };
905
906 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
907
908 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
909 u16 pending_idx,
910 struct xen_netif_tx_request *txp,
911 struct gnttab_map_grant_ref *mop)
912 {
913 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
914 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
915 GNTMAP_host_map | GNTMAP_readonly,
916 txp->gref, queue->vif->domid);
917
918 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
919 sizeof(*txp));
920 }
921
922 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
923 {
924 struct sk_buff *skb =
925 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
926 GFP_ATOMIC | __GFP_NOWARN);
927 if (unlikely(skb == NULL))
928 return NULL;
929
930 /* Packets passed to netif_rx() must have some headroom. */
931 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
932
933 /* Initialize it here to avoid later surprises */
934 skb_shinfo(skb)->destructor_arg = NULL;
935
936 return skb;
937 }
938
939 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
940 struct sk_buff *skb,
941 struct xen_netif_tx_request *txp,
942 struct gnttab_map_grant_ref *gop)
943 {
944 struct skb_shared_info *shinfo = skb_shinfo(skb);
945 skb_frag_t *frags = shinfo->frags;
946 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
947 int start;
948 pending_ring_idx_t index;
949 unsigned int nr_slots, frag_overflow = 0;
950
951 /* At this point shinfo->nr_frags is in fact the number of
952 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
953 */
954 if (shinfo->nr_frags > MAX_SKB_FRAGS) {
955 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
956 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
957 shinfo->nr_frags = MAX_SKB_FRAGS;
958 }
959 nr_slots = shinfo->nr_frags;
960
961 /* Skip first skb fragment if it is on same page as header fragment. */
962 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
963
964 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
965 shinfo->nr_frags++, txp++, gop++) {
966 index = pending_index(queue->pending_cons++);
967 pending_idx = queue->pending_ring[index];
968 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
969 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
970 }
971
972 if (frag_overflow) {
973 struct sk_buff *nskb = xenvif_alloc_skb(0);
974 if (unlikely(nskb == NULL)) {
975 if (net_ratelimit())
976 netdev_err(queue->vif->dev,
977 "Can't allocate the frag_list skb.\n");
978 return NULL;
979 }
980
981 shinfo = skb_shinfo(nskb);
982 frags = shinfo->frags;
983
984 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
985 shinfo->nr_frags++, txp++, gop++) {
986 index = pending_index(queue->pending_cons++);
987 pending_idx = queue->pending_ring[index];
988 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
989 frag_set_pending_idx(&frags[shinfo->nr_frags],
990 pending_idx);
991 }
992
993 skb_shinfo(skb)->frag_list = nskb;
994 }
995
996 return gop;
997 }
998
999 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
1000 u16 pending_idx,
1001 grant_handle_t handle)
1002 {
1003 if (unlikely(queue->grant_tx_handle[pending_idx] !=
1004 NETBACK_INVALID_HANDLE)) {
1005 netdev_err(queue->vif->dev,
1006 "Trying to overwrite active handle! pending_idx: %x\n",
1007 pending_idx);
1008 BUG();
1009 }
1010 queue->grant_tx_handle[pending_idx] = handle;
1011 }
1012
1013 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
1014 u16 pending_idx)
1015 {
1016 if (unlikely(queue->grant_tx_handle[pending_idx] ==
1017 NETBACK_INVALID_HANDLE)) {
1018 netdev_err(queue->vif->dev,
1019 "Trying to unmap invalid handle! pending_idx: %x\n",
1020 pending_idx);
1021 BUG();
1022 }
1023 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
1024 }
1025
1026 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
1027 struct sk_buff *skb,
1028 struct gnttab_map_grant_ref **gopp_map,
1029 struct gnttab_copy **gopp_copy)
1030 {
1031 struct gnttab_map_grant_ref *gop_map = *gopp_map;
1032 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1033 /* This always points to the shinfo of the skb being checked, which
1034 * could be either the first or the one on the frag_list
1035 */
1036 struct skb_shared_info *shinfo = skb_shinfo(skb);
1037 /* If this is non-NULL, we are currently checking the frag_list skb, and
1038 * this points to the shinfo of the first one
1039 */
1040 struct skb_shared_info *first_shinfo = NULL;
1041 int nr_frags = shinfo->nr_frags;
1042 const bool sharedslot = nr_frags &&
1043 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
1044 int i, err;
1045
1046 /* Check status of header. */
1047 err = (*gopp_copy)->status;
1048 if (unlikely(err)) {
1049 if (net_ratelimit())
1050 netdev_dbg(queue->vif->dev,
1051 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
1052 (*gopp_copy)->status,
1053 pending_idx,
1054 (*gopp_copy)->source.u.ref);
1055 /* The first frag might still have this slot mapped */
1056 if (!sharedslot)
1057 xenvif_idx_release(queue, pending_idx,
1058 XEN_NETIF_RSP_ERROR);
1059 }
1060 (*gopp_copy)++;
1061
1062 check_frags:
1063 for (i = 0; i < nr_frags; i++, gop_map++) {
1064 int j, newerr;
1065
1066 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1067
1068 /* Check error status: if okay then remember grant handle. */
1069 newerr = gop_map->status;
1070
1071 if (likely(!newerr)) {
1072 xenvif_grant_handle_set(queue,
1073 pending_idx,
1074 gop_map->handle);
1075 /* Had a previous error? Invalidate this fragment. */
1076 if (unlikely(err)) {
1077 xenvif_idx_unmap(queue, pending_idx);
1078 /* If the mapping of the first frag was OK, but
1079 * the header's copy failed, and they are
1080 * sharing a slot, send an error
1081 */
1082 if (i == 0 && sharedslot)
1083 xenvif_idx_release(queue, pending_idx,
1084 XEN_NETIF_RSP_ERROR);
1085 else
1086 xenvif_idx_release(queue, pending_idx,
1087 XEN_NETIF_RSP_OKAY);
1088 }
1089 continue;
1090 }
1091
1092 /* Error on this fragment: respond to client with an error. */
1093 if (net_ratelimit())
1094 netdev_dbg(queue->vif->dev,
1095 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
1096 i,
1097 gop_map->status,
1098 pending_idx,
1099 gop_map->ref);
1100
1101 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
1102
1103 /* Not the first error? Preceding frags already invalidated. */
1104 if (err)
1105 continue;
1106
1107 /* First error: if the header haven't shared a slot with the
1108 * first frag, release it as well.
1109 */
1110 if (!sharedslot)
1111 xenvif_idx_release(queue,
1112 XENVIF_TX_CB(skb)->pending_idx,
1113 XEN_NETIF_RSP_OKAY);
1114
1115 /* Invalidate preceding fragments of this skb. */
1116 for (j = 0; j < i; j++) {
1117 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1118 xenvif_idx_unmap(queue, pending_idx);
1119 xenvif_idx_release(queue, pending_idx,
1120 XEN_NETIF_RSP_OKAY);
1121 }
1122
1123 /* And if we found the error while checking the frag_list, unmap
1124 * the first skb's frags
1125 */
1126 if (first_shinfo) {
1127 for (j = 0; j < first_shinfo->nr_frags; j++) {
1128 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
1129 xenvif_idx_unmap(queue, pending_idx);
1130 xenvif_idx_release(queue, pending_idx,
1131 XEN_NETIF_RSP_OKAY);
1132 }
1133 }
1134
1135 /* Remember the error: invalidate all subsequent fragments. */
1136 err = newerr;
1137 }
1138
1139 if (skb_has_frag_list(skb) && !first_shinfo) {
1140 first_shinfo = skb_shinfo(skb);
1141 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1142 nr_frags = shinfo->nr_frags;
1143
1144 goto check_frags;
1145 }
1146
1147 *gopp_map = gop_map;
1148 return err;
1149 }
1150
1151 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1152 {
1153 struct skb_shared_info *shinfo = skb_shinfo(skb);
1154 int nr_frags = shinfo->nr_frags;
1155 int i;
1156 u16 prev_pending_idx = INVALID_PENDING_IDX;
1157
1158 for (i = 0; i < nr_frags; i++) {
1159 skb_frag_t *frag = shinfo->frags + i;
1160 struct xen_netif_tx_request *txp;
1161 struct page *page;
1162 u16 pending_idx;
1163
1164 pending_idx = frag_get_pending_idx(frag);
1165
1166 /* If this is not the first frag, chain it to the previous*/
1167 if (prev_pending_idx == INVALID_PENDING_IDX)
1168 skb_shinfo(skb)->destructor_arg =
1169 &callback_param(queue, pending_idx);
1170 else
1171 callback_param(queue, prev_pending_idx).ctx =
1172 &callback_param(queue, pending_idx);
1173
1174 callback_param(queue, pending_idx).ctx = NULL;
1175 prev_pending_idx = pending_idx;
1176
1177 txp = &queue->pending_tx_info[pending_idx].req;
1178 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1179 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1180 skb->len += txp->size;
1181 skb->data_len += txp->size;
1182 skb->truesize += txp->size;
1183
1184 /* Take an extra reference to offset network stack's put_page */
1185 get_page(queue->mmap_pages[pending_idx]);
1186 }
1187 /* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
1188 * overlaps with "index", and "mapping" is not set. I think mapping
1189 * should be set. If delivered to local stack, it would drop this
1190 * skb in sk_filter unless the socket has the right to use it.
1191 */
1192 skb->pfmemalloc = false;
1193 }
1194
1195 static int xenvif_get_extras(struct xenvif_queue *queue,
1196 struct xen_netif_extra_info *extras,
1197 int work_to_do)
1198 {
1199 struct xen_netif_extra_info extra;
1200 RING_IDX cons = queue->tx.req_cons;
1201
1202 do {
1203 if (unlikely(work_to_do-- <= 0)) {
1204 netdev_err(queue->vif->dev, "Missing extra info\n");
1205 xenvif_fatal_tx_err(queue->vif);
1206 return -EBADR;
1207 }
1208
1209 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons),
1210 sizeof(extra));
1211 if (unlikely(!extra.type ||
1212 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1213 queue->tx.req_cons = ++cons;
1214 netdev_err(queue->vif->dev,
1215 "Invalid extra type: %d\n", extra.type);
1216 xenvif_fatal_tx_err(queue->vif);
1217 return -EINVAL;
1218 }
1219
1220 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1221 queue->tx.req_cons = ++cons;
1222 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1223
1224 return work_to_do;
1225 }
1226
1227 static int xenvif_set_skb_gso(struct xenvif *vif,
1228 struct sk_buff *skb,
1229 struct xen_netif_extra_info *gso)
1230 {
1231 if (!gso->u.gso.size) {
1232 netdev_err(vif->dev, "GSO size must not be zero.\n");
1233 xenvif_fatal_tx_err(vif);
1234 return -EINVAL;
1235 }
1236
1237 switch (gso->u.gso.type) {
1238 case XEN_NETIF_GSO_TYPE_TCPV4:
1239 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1240 break;
1241 case XEN_NETIF_GSO_TYPE_TCPV6:
1242 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1243 break;
1244 default:
1245 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1246 xenvif_fatal_tx_err(vif);
1247 return -EINVAL;
1248 }
1249
1250 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1251 /* gso_segs will be calculated later */
1252
1253 return 0;
1254 }
1255
1256 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1257 {
1258 bool recalculate_partial_csum = false;
1259
1260 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1261 * peers can fail to set NETRXF_csum_blank when sending a GSO
1262 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1263 * recalculate the partial checksum.
1264 */
1265 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1266 queue->stats.rx_gso_checksum_fixup++;
1267 skb->ip_summed = CHECKSUM_PARTIAL;
1268 recalculate_partial_csum = true;
1269 }
1270
1271 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1272 if (skb->ip_summed != CHECKSUM_PARTIAL)
1273 return 0;
1274
1275 return skb_checksum_setup(skb, recalculate_partial_csum);
1276 }
1277
1278 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1279 {
1280 u64 now = get_jiffies_64();
1281 u64 next_credit = queue->credit_window_start +
1282 msecs_to_jiffies(queue->credit_usec / 1000);
1283
1284 /* Timer could already be pending in rare cases. */
1285 if (timer_pending(&queue->credit_timeout))
1286 return true;
1287
1288 /* Passed the point where we can replenish credit? */
1289 if (time_after_eq64(now, next_credit)) {
1290 queue->credit_window_start = now;
1291 tx_add_credit(queue);
1292 }
1293
1294 /* Still too big to send right now? Set a callback. */
1295 if (size > queue->remaining_credit) {
1296 queue->credit_timeout.data =
1297 (unsigned long)queue;
1298 queue->credit_timeout.function =
1299 tx_credit_callback;
1300 mod_timer(&queue->credit_timeout,
1301 next_credit);
1302 queue->credit_window_start = next_credit;
1303
1304 return true;
1305 }
1306
1307 return false;
1308 }
1309
1310 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1311 int budget,
1312 unsigned *copy_ops,
1313 unsigned *map_ops)
1314 {
1315 struct gnttab_map_grant_ref *gop = queue->tx_map_ops, *request_gop;
1316 struct sk_buff *skb;
1317 int ret;
1318
1319 while (skb_queue_len(&queue->tx_queue) < budget) {
1320 struct xen_netif_tx_request txreq;
1321 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1322 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1323 u16 pending_idx;
1324 RING_IDX idx;
1325 int work_to_do;
1326 unsigned int data_len;
1327 pending_ring_idx_t index;
1328
1329 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1330 XEN_NETIF_TX_RING_SIZE) {
1331 netdev_err(queue->vif->dev,
1332 "Impossible number of requests. "
1333 "req_prod %d, req_cons %d, size %ld\n",
1334 queue->tx.sring->req_prod, queue->tx.req_cons,
1335 XEN_NETIF_TX_RING_SIZE);
1336 xenvif_fatal_tx_err(queue->vif);
1337 break;
1338 }
1339
1340 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1341 if (!work_to_do)
1342 break;
1343
1344 idx = queue->tx.req_cons;
1345 rmb(); /* Ensure that we see the request before we copy it. */
1346 memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq));
1347
1348 /* Credit-based scheduling. */
1349 if (txreq.size > queue->remaining_credit &&
1350 tx_credit_exceeded(queue, txreq.size))
1351 break;
1352
1353 queue->remaining_credit -= txreq.size;
1354
1355 work_to_do--;
1356 queue->tx.req_cons = ++idx;
1357
1358 memset(extras, 0, sizeof(extras));
1359 if (txreq.flags & XEN_NETTXF_extra_info) {
1360 work_to_do = xenvif_get_extras(queue, extras,
1361 work_to_do);
1362 idx = queue->tx.req_cons;
1363 if (unlikely(work_to_do < 0))
1364 break;
1365 }
1366
1367 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1368 if (unlikely(ret < 0))
1369 break;
1370
1371 idx += ret;
1372
1373 if (unlikely(txreq.size < ETH_HLEN)) {
1374 netdev_dbg(queue->vif->dev,
1375 "Bad packet size: %d\n", txreq.size);
1376 xenvif_tx_err(queue, &txreq, idx);
1377 break;
1378 }
1379
1380 /* No crossing a page as the payload mustn't fragment. */
1381 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1382 netdev_err(queue->vif->dev,
1383 "txreq.offset: %x, size: %u, end: %lu\n",
1384 txreq.offset, txreq.size,
1385 (txreq.offset&~PAGE_MASK) + txreq.size);
1386 xenvif_fatal_tx_err(queue->vif);
1387 break;
1388 }
1389
1390 index = pending_index(queue->pending_cons);
1391 pending_idx = queue->pending_ring[index];
1392
1393 data_len = (txreq.size > PKT_PROT_LEN &&
1394 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1395 PKT_PROT_LEN : txreq.size;
1396
1397 skb = xenvif_alloc_skb(data_len);
1398 if (unlikely(skb == NULL)) {
1399 netdev_dbg(queue->vif->dev,
1400 "Can't allocate a skb in start_xmit.\n");
1401 xenvif_tx_err(queue, &txreq, idx);
1402 break;
1403 }
1404
1405 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1406 struct xen_netif_extra_info *gso;
1407 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1408
1409 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1410 /* Failure in xenvif_set_skb_gso is fatal. */
1411 kfree_skb(skb);
1412 break;
1413 }
1414 }
1415
1416 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1417
1418 __skb_put(skb, data_len);
1419 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1420 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1421 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1422
1423 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1424 virt_to_mfn(skb->data);
1425 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1426 queue->tx_copy_ops[*copy_ops].dest.offset =
1427 offset_in_page(skb->data);
1428
1429 queue->tx_copy_ops[*copy_ops].len = data_len;
1430 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1431
1432 (*copy_ops)++;
1433
1434 skb_shinfo(skb)->nr_frags = ret;
1435 if (data_len < txreq.size) {
1436 skb_shinfo(skb)->nr_frags++;
1437 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1438 pending_idx);
1439 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
1440 gop++;
1441 } else {
1442 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1443 INVALID_PENDING_IDX);
1444 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
1445 sizeof(txreq));
1446 }
1447
1448 queue->pending_cons++;
1449
1450 request_gop = xenvif_get_requests(queue, skb, txfrags, gop);
1451 if (request_gop == NULL) {
1452 kfree_skb(skb);
1453 xenvif_tx_err(queue, &txreq, idx);
1454 break;
1455 }
1456 gop = request_gop;
1457
1458 __skb_queue_tail(&queue->tx_queue, skb);
1459
1460 queue->tx.req_cons = idx;
1461
1462 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1463 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1464 break;
1465 }
1466
1467 (*map_ops) = gop - queue->tx_map_ops;
1468 return;
1469 }
1470
1471 /* Consolidate skb with a frag_list into a brand new one with local pages on
1472 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1473 */
1474 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1475 {
1476 unsigned int offset = skb_headlen(skb);
1477 skb_frag_t frags[MAX_SKB_FRAGS];
1478 int i;
1479 struct ubuf_info *uarg;
1480 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1481
1482 queue->stats.tx_zerocopy_sent += 2;
1483 queue->stats.tx_frag_overflow++;
1484
1485 xenvif_fill_frags(queue, nskb);
1486 /* Subtract frags size, we will correct it later */
1487 skb->truesize -= skb->data_len;
1488 skb->len += nskb->len;
1489 skb->data_len += nskb->len;
1490
1491 /* create a brand new frags array and coalesce there */
1492 for (i = 0; offset < skb->len; i++) {
1493 struct page *page;
1494 unsigned int len;
1495
1496 BUG_ON(i >= MAX_SKB_FRAGS);
1497 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
1498 if (!page) {
1499 int j;
1500 skb->truesize += skb->data_len;
1501 for (j = 0; j < i; j++)
1502 put_page(frags[j].page.p);
1503 return -ENOMEM;
1504 }
1505
1506 if (offset + PAGE_SIZE < skb->len)
1507 len = PAGE_SIZE;
1508 else
1509 len = skb->len - offset;
1510 if (skb_copy_bits(skb, offset, page_address(page), len))
1511 BUG();
1512
1513 offset += len;
1514 frags[i].page.p = page;
1515 frags[i].page_offset = 0;
1516 skb_frag_size_set(&frags[i], len);
1517 }
1518 /* swap out with old one */
1519 memcpy(skb_shinfo(skb)->frags,
1520 frags,
1521 i * sizeof(skb_frag_t));
1522 skb_shinfo(skb)->nr_frags = i;
1523 skb->truesize += i * PAGE_SIZE;
1524
1525 /* remove traces of mapped pages and frag_list */
1526 skb_frag_list_init(skb);
1527 uarg = skb_shinfo(skb)->destructor_arg;
1528 uarg->callback(uarg, true);
1529 skb_shinfo(skb)->destructor_arg = NULL;
1530
1531 skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1532 kfree_skb(nskb);
1533
1534 return 0;
1535 }
1536
1537 static int xenvif_tx_submit(struct xenvif_queue *queue)
1538 {
1539 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1540 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1541 struct sk_buff *skb;
1542 int work_done = 0;
1543
1544 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1545 struct xen_netif_tx_request *txp;
1546 u16 pending_idx;
1547 unsigned data_len;
1548
1549 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1550 txp = &queue->pending_tx_info[pending_idx].req;
1551
1552 /* Check the remap error code. */
1553 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1554 /* If there was an error, xenvif_tx_check_gop is
1555 * expected to release all the frags which were mapped,
1556 * so kfree_skb shouldn't do it again
1557 */
1558 skb_shinfo(skb)->nr_frags = 0;
1559 if (skb_has_frag_list(skb)) {
1560 struct sk_buff *nskb =
1561 skb_shinfo(skb)->frag_list;
1562 skb_shinfo(nskb)->nr_frags = 0;
1563 }
1564 kfree_skb(skb);
1565 continue;
1566 }
1567
1568 data_len = skb->len;
1569 callback_param(queue, pending_idx).ctx = NULL;
1570 if (data_len < txp->size) {
1571 /* Append the packet payload as a fragment. */
1572 txp->offset += data_len;
1573 txp->size -= data_len;
1574 } else {
1575 /* Schedule a response immediately. */
1576 xenvif_idx_release(queue, pending_idx,
1577 XEN_NETIF_RSP_OKAY);
1578 }
1579
1580 if (txp->flags & XEN_NETTXF_csum_blank)
1581 skb->ip_summed = CHECKSUM_PARTIAL;
1582 else if (txp->flags & XEN_NETTXF_data_validated)
1583 skb->ip_summed = CHECKSUM_UNNECESSARY;
1584
1585 xenvif_fill_frags(queue, skb);
1586
1587 if (unlikely(skb_has_frag_list(skb))) {
1588 if (xenvif_handle_frag_list(queue, skb)) {
1589 if (net_ratelimit())
1590 netdev_err(queue->vif->dev,
1591 "Not enough memory to consolidate frag_list!\n");
1592 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1593 kfree_skb(skb);
1594 continue;
1595 }
1596 }
1597
1598 if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
1599 int target = min_t(int, skb->len, PKT_PROT_LEN);
1600 __pskb_pull_tail(skb, target - skb_headlen(skb));
1601 }
1602
1603 skb->dev = queue->vif->dev;
1604 skb->protocol = eth_type_trans(skb, skb->dev);
1605 skb_reset_network_header(skb);
1606
1607 if (checksum_setup(queue, skb)) {
1608 netdev_dbg(queue->vif->dev,
1609 "Can't setup checksum in net_tx_action\n");
1610 /* We have to set this flag to trigger the callback */
1611 if (skb_shinfo(skb)->destructor_arg)
1612 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1613 kfree_skb(skb);
1614 continue;
1615 }
1616
1617 skb_probe_transport_header(skb, 0);
1618
1619 /* If the packet is GSO then we will have just set up the
1620 * transport header offset in checksum_setup so it's now
1621 * straightforward to calculate gso_segs.
1622 */
1623 if (skb_is_gso(skb)) {
1624 int mss = skb_shinfo(skb)->gso_size;
1625 int hdrlen = skb_transport_header(skb) -
1626 skb_mac_header(skb) +
1627 tcp_hdrlen(skb);
1628
1629 skb_shinfo(skb)->gso_segs =
1630 DIV_ROUND_UP(skb->len - hdrlen, mss);
1631 }
1632
1633 queue->stats.rx_bytes += skb->len;
1634 queue->stats.rx_packets++;
1635
1636 work_done++;
1637
1638 /* Set this flag right before netif_receive_skb, otherwise
1639 * someone might think this packet already left netback, and
1640 * do a skb_copy_ubufs while we are still in control of the
1641 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1642 */
1643 if (skb_shinfo(skb)->destructor_arg) {
1644 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1645 queue->stats.tx_zerocopy_sent++;
1646 }
1647
1648 netif_receive_skb(skb);
1649 }
1650
1651 return work_done;
1652 }
1653
1654 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1655 {
1656 unsigned long flags;
1657 pending_ring_idx_t index;
1658 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1659
1660 /* This is the only place where we grab this lock, to protect callbacks
1661 * from each other.
1662 */
1663 spin_lock_irqsave(&queue->callback_lock, flags);
1664 do {
1665 u16 pending_idx = ubuf->desc;
1666 ubuf = (struct ubuf_info *) ubuf->ctx;
1667 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1668 MAX_PENDING_REQS);
1669 index = pending_index(queue->dealloc_prod);
1670 queue->dealloc_ring[index] = pending_idx;
1671 /* Sync with xenvif_tx_dealloc_action:
1672 * insert idx then incr producer.
1673 */
1674 smp_wmb();
1675 queue->dealloc_prod++;
1676 } while (ubuf);
1677 wake_up(&queue->dealloc_wq);
1678 spin_unlock_irqrestore(&queue->callback_lock, flags);
1679
1680 if (likely(zerocopy_success))
1681 queue->stats.tx_zerocopy_success++;
1682 else
1683 queue->stats.tx_zerocopy_fail++;
1684 }
1685
1686 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1687 {
1688 struct gnttab_unmap_grant_ref *gop;
1689 pending_ring_idx_t dc, dp;
1690 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1691 unsigned int i = 0;
1692
1693 dc = queue->dealloc_cons;
1694 gop = queue->tx_unmap_ops;
1695
1696 /* Free up any grants we have finished using */
1697 do {
1698 dp = queue->dealloc_prod;
1699
1700 /* Ensure we see all indices enqueued by all
1701 * xenvif_zerocopy_callback().
1702 */
1703 smp_rmb();
1704
1705 while (dc != dp) {
1706 BUG_ON(gop - queue->tx_unmap_ops > MAX_PENDING_REQS);
1707 pending_idx =
1708 queue->dealloc_ring[pending_index(dc++)];
1709
1710 pending_idx_release[gop-queue->tx_unmap_ops] =
1711 pending_idx;
1712 queue->pages_to_unmap[gop-queue->tx_unmap_ops] =
1713 queue->mmap_pages[pending_idx];
1714 gnttab_set_unmap_op(gop,
1715 idx_to_kaddr(queue, pending_idx),
1716 GNTMAP_host_map,
1717 queue->grant_tx_handle[pending_idx]);
1718 xenvif_grant_handle_reset(queue, pending_idx);
1719 ++gop;
1720 }
1721
1722 } while (dp != queue->dealloc_prod);
1723
1724 queue->dealloc_cons = dc;
1725
1726 if (gop - queue->tx_unmap_ops > 0) {
1727 int ret;
1728 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1729 NULL,
1730 queue->pages_to_unmap,
1731 gop - queue->tx_unmap_ops);
1732 if (ret) {
1733 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
1734 gop - queue->tx_unmap_ops, ret);
1735 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1736 if (gop[i].status != GNTST_okay)
1737 netdev_err(queue->vif->dev,
1738 " host_addr: %llx handle: %x status: %d\n",
1739 gop[i].host_addr,
1740 gop[i].handle,
1741 gop[i].status);
1742 }
1743 BUG();
1744 }
1745 }
1746
1747 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1748 xenvif_idx_release(queue, pending_idx_release[i],
1749 XEN_NETIF_RSP_OKAY);
1750 }
1751
1752
1753 /* Called after netfront has transmitted */
1754 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1755 {
1756 unsigned nr_mops, nr_cops = 0;
1757 int work_done, ret;
1758
1759 if (unlikely(!tx_work_todo(queue)))
1760 return 0;
1761
1762 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1763
1764 if (nr_cops == 0)
1765 return 0;
1766
1767 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1768 if (nr_mops != 0) {
1769 ret = gnttab_map_refs(queue->tx_map_ops,
1770 NULL,
1771 queue->pages_to_map,
1772 nr_mops);
1773 BUG_ON(ret);
1774 }
1775
1776 work_done = xenvif_tx_submit(queue);
1777
1778 return work_done;
1779 }
1780
1781 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1782 u8 status)
1783 {
1784 struct pending_tx_info *pending_tx_info;
1785 pending_ring_idx_t index;
1786 unsigned long flags;
1787
1788 pending_tx_info = &queue->pending_tx_info[pending_idx];
1789 spin_lock_irqsave(&queue->response_lock, flags);
1790 make_tx_response(queue, &pending_tx_info->req, status);
1791 index = pending_index(queue->pending_prod);
1792 queue->pending_ring[index] = pending_idx;
1793 /* TX shouldn't use the index before we give it back here */
1794 mb();
1795 queue->pending_prod++;
1796 spin_unlock_irqrestore(&queue->response_lock, flags);
1797 }
1798
1799
1800 static void make_tx_response(struct xenvif_queue *queue,
1801 struct xen_netif_tx_request *txp,
1802 s8 st)
1803 {
1804 RING_IDX i = queue->tx.rsp_prod_pvt;
1805 struct xen_netif_tx_response *resp;
1806 int notify;
1807
1808 resp = RING_GET_RESPONSE(&queue->tx, i);
1809 resp->id = txp->id;
1810 resp->status = st;
1811
1812 if (txp->flags & XEN_NETTXF_extra_info)
1813 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1814
1815 queue->tx.rsp_prod_pvt = ++i;
1816 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1817 if (notify)
1818 notify_remote_via_irq(queue->tx_irq);
1819 }
1820
1821 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1822 u16 id,
1823 s8 st,
1824 u16 offset,
1825 u16 size,
1826 u16 flags)
1827 {
1828 RING_IDX i = queue->rx.rsp_prod_pvt;
1829 struct xen_netif_rx_response *resp;
1830
1831 resp = RING_GET_RESPONSE(&queue->rx, i);
1832 resp->offset = offset;
1833 resp->flags = flags;
1834 resp->id = id;
1835 resp->status = (s16)size;
1836 if (st < 0)
1837 resp->status = (s16)st;
1838
1839 queue->rx.rsp_prod_pvt = ++i;
1840
1841 return resp;
1842 }
1843
1844 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1845 {
1846 int ret;
1847 struct gnttab_unmap_grant_ref tx_unmap_op;
1848
1849 gnttab_set_unmap_op(&tx_unmap_op,
1850 idx_to_kaddr(queue, pending_idx),
1851 GNTMAP_host_map,
1852 queue->grant_tx_handle[pending_idx]);
1853 xenvif_grant_handle_reset(queue, pending_idx);
1854
1855 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1856 &queue->mmap_pages[pending_idx], 1);
1857 if (ret) {
1858 netdev_err(queue->vif->dev,
1859 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
1860 ret,
1861 pending_idx,
1862 tx_unmap_op.host_addr,
1863 tx_unmap_op.handle,
1864 tx_unmap_op.status);
1865 BUG();
1866 }
1867 }
1868
1869 static inline int rx_work_todo(struct xenvif_queue *queue)
1870 {
1871 return (!skb_queue_empty(&queue->rx_queue) &&
1872 xenvif_rx_ring_slots_available(queue, queue->rx_last_skb_slots)) ||
1873 queue->rx_queue_purge;
1874 }
1875
1876 static inline int tx_work_todo(struct xenvif_queue *queue)
1877 {
1878 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1879 return 1;
1880
1881 return 0;
1882 }
1883
1884 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1885 {
1886 return queue->dealloc_cons != queue->dealloc_prod;
1887 }
1888
1889 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1890 {
1891 if (queue->tx.sring)
1892 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1893 queue->tx.sring);
1894 if (queue->rx.sring)
1895 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1896 queue->rx.sring);
1897 }
1898
1899 int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1900 grant_ref_t tx_ring_ref,
1901 grant_ref_t rx_ring_ref)
1902 {
1903 void *addr;
1904 struct xen_netif_tx_sring *txs;
1905 struct xen_netif_rx_sring *rxs;
1906
1907 int err = -ENOMEM;
1908
1909 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1910 tx_ring_ref, &addr);
1911 if (err)
1912 goto err;
1913
1914 txs = (struct xen_netif_tx_sring *)addr;
1915 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
1916
1917 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1918 rx_ring_ref, &addr);
1919 if (err)
1920 goto err;
1921
1922 rxs = (struct xen_netif_rx_sring *)addr;
1923 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
1924
1925 return 0;
1926
1927 err:
1928 xenvif_unmap_frontend_rings(queue);
1929 return err;
1930 }
1931
1932 static void xenvif_start_queue(struct xenvif_queue *queue)
1933 {
1934 if (xenvif_schedulable(queue->vif))
1935 xenvif_wake_queue(queue);
1936 }
1937
1938 int xenvif_kthread_guest_rx(void *data)
1939 {
1940 struct xenvif_queue *queue = data;
1941 struct sk_buff *skb;
1942
1943 while (!kthread_should_stop()) {
1944 wait_event_interruptible(queue->wq,
1945 rx_work_todo(queue) ||
1946 queue->vif->disabled ||
1947 kthread_should_stop());
1948
1949 /* This frontend is found to be rogue, disable it in
1950 * kthread context. Currently this is only set when
1951 * netback finds out frontend sends malformed packet,
1952 * but we cannot disable the interface in softirq
1953 * context so we defer it here, if this thread is
1954 * associated with queue 0.
1955 */
1956 if (unlikely(queue->vif->disabled && netif_carrier_ok(queue->vif->dev) && queue->id == 0))
1957 xenvif_carrier_off(queue->vif);
1958
1959 if (kthread_should_stop())
1960 break;
1961
1962 if (queue->rx_queue_purge) {
1963 skb_queue_purge(&queue->rx_queue);
1964 queue->rx_queue_purge = false;
1965 }
1966
1967 if (!skb_queue_empty(&queue->rx_queue))
1968 xenvif_rx_action(queue);
1969
1970 if (skb_queue_empty(&queue->rx_queue) &&
1971 xenvif_queue_stopped(queue)) {
1972 del_timer_sync(&queue->wake_queue);
1973 xenvif_start_queue(queue);
1974 }
1975
1976 cond_resched();
1977 }
1978
1979 /* Bin any remaining skbs */
1980 while ((skb = skb_dequeue(&queue->rx_queue)) != NULL)
1981 dev_kfree_skb(skb);
1982
1983 return 0;
1984 }
1985
1986 int xenvif_dealloc_kthread(void *data)
1987 {
1988 struct xenvif_queue *queue = data;
1989
1990 while (!kthread_should_stop()) {
1991 wait_event_interruptible(queue->dealloc_wq,
1992 tx_dealloc_work_todo(queue) ||
1993 kthread_should_stop());
1994 if (kthread_should_stop())
1995 break;
1996
1997 xenvif_tx_dealloc_action(queue);
1998 cond_resched();
1999 }
2000
2001 /* Unmap anything remaining*/
2002 if (tx_dealloc_work_todo(queue))
2003 xenvif_tx_dealloc_action(queue);
2004
2005 return 0;
2006 }
2007
2008 static int __init netback_init(void)
2009 {
2010 int rc = 0;
2011
2012 if (!xen_domain())
2013 return -ENODEV;
2014
2015 /* Allow as many queues as there are CPUs, by default */
2016 xenvif_max_queues = num_online_cpus();
2017
2018 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2019 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2020 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2021 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2022 }
2023
2024 rc = xenvif_xenbus_init();
2025 if (rc)
2026 goto failed_init;
2027
2028 rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
2029
2030 return 0;
2031
2032 failed_init:
2033 return rc;
2034 }
2035
2036 module_init(netback_init);
2037
2038 static void __exit netback_fini(void)
2039 {
2040 xenvif_xenbus_fini();
2041 }
2042 module_exit(netback_fini);
2043
2044 MODULE_LICENSE("Dual BSD/GPL");
2045 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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